Graphical Demonstration of Serviceability Analysis

A graphical interactive computer program (GISALLE) has been developed using state of the art computer graphics to estimate the seismic performance of water supply systems. GISALLE is developed to (i) generate damage states for lifelines consistent with the seismic intensity at the site; (ii) perform hydraulic analysis for simulated damage state of the system; and (iii) develop statistics on the available flow for postulated levels of seismic intensity. GISALLE is based on an efficient new algorithm for hydraulic analysis developed recently at Cornell. The algorithm simultaneously solves equations of flow continuity at each node and energy balance for each pipe. It can handle situations in which some of the pipelines of a system have no or partial flow. Such situations occur frequently in systems with significant differences in elevation and/or systems in advanced damage states. Fragility curves and other measures are developed to evaluate the seismic performance of the Auxiliary Water Supply System (AWSS) in San Francisco.